@misc{indiciaec665a95b97db,
  title = {Geologic framework and environmental geology of the Summitville, Colorado acid-sulfate mineral deposit},
  author = {J. E. Gray and M.F. Coolbaugh and G.S. Plumlee},
  year = {1993},
  doi = {10.3133/ofr93677},
  url = {https://pubs.usgs.gov/publication/ofr93677},
  note = {Source identifier: ofr93677}
}